<![CDATA[Compass accuracy / resolution]]>Hi,

The data sheet of the OpenIMU300ZA claims that the resolution of the magnetic sensor is ~0.3 mGauss.
Do you have an approximation of how it relates to the resolution in degrees of the compass? (assuming that the imu is calibrated for hard/soft iron and located at sea level)

Do you have an approximation for the accuracy of the compass app (which also takes the gyro and accelerometer data into account)?

Thanks

]]>https://forum.aceinna.com//topic/43/compass-accuracy-resolutionRSS for NodeTue, 12 May 2026 07:31:35 GMTSun, 16 Jun 2019 14:19:41 GMT60<![CDATA[Reply to Compass accuracy / resolution on Sun, 16 Jun 2019 14:19:41 GMT]]>Hi,

The data sheet of the OpenIMU300ZA claims that the resolution of the magnetic sensor is ~0.3 mGauss.
Do you have an approximation of how it relates to the resolution in degrees of the compass? (assuming that the imu is calibrated for hard/soft iron and located at sea level)

Do you have an approximation for the accuracy of the compass app (which also takes the gyro and accelerometer data into account)?

Thanks

]]>https://forum.aceinna.com//post/106https://forum.aceinna.com//post/106Sun, 16 Jun 2019 14:19:41 GMT<![CDATA[Reply to Compass accuracy / resolution on Mon, 17 Jun 2019 12:59:21 GMT]]>Hi Ron，
The OpenIMU300ZA factory firmware version released only with IMU app currently, then verify the IMU performance and list the parameter on datasheet. I will contact with factory and send you an approximation accuracy for reference. Btw, what is the application scenarios of the compass you choose, In car or on ship?

]]>https://forum.aceinna.com//post/109https://forum.aceinna.com//post/109Mon, 17 Jun 2019 12:59:21 GMT<![CDATA[Reply to Compass accuracy / resolution on Mon, 17 Jun 2019 20:26:33 GMT]]>It is used on a robot (which drives on a floor) indoors.

Thank you

]]>https://forum.aceinna.com//post/110https://forum.aceinna.com//post/110Mon, 17 Jun 2019 20:26:33 GMT<![CDATA[Reply to Compass accuracy / resolution on Tue, 18 Jun 2019 08:47:46 GMT]]>2019-06-18_16h38_09.jpg

Hi Ron,
I test ecompass application in office desktop, calibrate the mag sensor and add the result to gDefaultUserConfig struct in UserConfiguration.c file:
.hardIron_X = -0.13071,
.hardIron_Y = -0.06094,
.softIron_Ratio = 0.93736,
.softIron_Angle = 0.95718

use the openimu python driver(download from github) connect the https://developers.aceinna.com/record and found the heading error with an approximation 0.4 degree when i place the openimu300ZA EVB x axis heading north.

]]>https://forum.aceinna.com//post/111https://forum.aceinna.com//post/111Tue, 18 Jun 2019 08:47:46 GMT<![CDATA[Reply to Compass accuracy / resolution on Tue, 25 Jun 2019 08:38:29 GMT]]>Assumption: IMU is calibrated for hard/soft iron and located at sea level
   Take heading angle A as example, A = atan2(Mag_y, Mag_x), so evaluate the resolution influence should be based on combination of Mag_x and Mag_y.
Evaluation: dived to 2 conditions
   1. one of x, y axis Mag value is 0. If Mag_x = 0, +/- 0.3mGauss change of Mag_y does not result in any impact.
  2. both x & y Mag value are not 0. After calculation based on different Mag_x & Mag_y(different angles), the resolution 0.3mGauss could leads several 0.01 degree change.
So the resolution of IMU have negligible influence on angle heading generally.

]]>https://forum.aceinna.com//post/118https://forum.aceinna.com//post/118Tue, 25 Jun 2019 08:38:29 GMT